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What is Pugh Matrix?
Pugh Matrix is a tool by which you can logically compare different options on the basis of some predefined criterion. This in turns will help with the selection of the best possible option.
Pugh Matrix is not only used very frequently in DMADV (Define, Measure, Analysis, Design, Validate) and DFSS (Design for Six Sigma) projects, it is very useful for validating multiple concepts of your day to day design engineering profession.
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How to create Pugh Matrix?
- Choose: Choose the options to be compared. For example, if you are involved in a project of designing a bracket and then you may select three designed concepts (say concept 1, concept 2 and concept 3).
- Selection Criteria: Study your customer requirements to drill down different selection criteria. For the three bracket design concepts your selection criteria may be: Weight, Manufacturability, Strength and Aesthetics.
- Set Reference: Most of the time you may be taking reference of some existing concept for designing new one. This existing concept should be taken as reference for comparing.
- Set Weightage: All the selection criteria are not equally important, so you have to give weightage for each of the selection criteria. For the above example, “strength" may be given a weightage of 10, manufacturability may be of 8, weight of 6 and aesthetics may be of 4.
- Compare: Compare all the individual concepts for different selection criteria with respect to the reference concept. If a concept is better than reference put +1, if not as good as reference put -1 and if similar to reference put 0.
- Calculate: Calculate weighted sum for each concept. The concept which got maximum score is the best on
See the already discussed bracket design example in Pugh Matrix format below (Click the image to enlarge it):
In the above example, Concept-1 got total sum of 14 (6 x 0 + 8 x 1 + 10 x 1 + 4 x (-1) = 14). Similarly we have calculated sum for all the concepts. As Concept-1 got highest sum hence this is the best concept here.
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Pugh matrix is a useful design engineering decision making tool. It is widely used for Six Sigma projects. Effective judgments about putting the weightage values are important in order to get full benefits of Pugh Matrix.